剑指offer（19）：顺时针打印矩阵

题目描述

输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字，例如，如果输入如下4 X 4矩阵： 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.

 

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {
        vector<int> result;
        if(!matrix.size()) return result;
        int row = matrix.size();
        int column = matrix[0].size();
        double minElement = min(row, column);
        int times = ceil(minElement / 2.0);
        int rowStart = 0;
        int rowEnd = row-1;
        int columnStart = 0;
        int columnEnd = column-1;
        int columnIndex = columnStart;
        int rowIndex = rowStart;
        for(int i=0;i<times;i++){
            columnIndex = columnStart;
            rowIndex = rowStart;
            while(columnIndex<=columnEnd){
                result.push_back(matrix[rowIndex][columnIndex]);
                columnIndex++;
            }
            if(rowStart == rowEnd) return result;
            columnIndex--;
            rowIndex++;
            while(rowIndex<=rowEnd){
                result.push_back(matrix[rowIndex][columnIndex]);
                rowIndex++;
            }
            if(columnStart == columnEnd) return result;
            columnIndex--;
            rowIndex--;
            while(columnIndex>=columnStart){
                result.push_back(matrix[rowIndex][columnIndex]);
                columnIndex--;
            }
            if(rowStart+1 == rowEnd) return result;
            columnIndex++;
            rowIndex--;
            while(rowIndex>rowStart){
                result.push_back(matrix[rowIndex][columnIndex]);
                rowIndex--;
            }
            columnStart++;
            columnEnd--;
            rowStart++;
            rowEnd--;
        }
        return result;
    }
};